Siblings Megumu and Mitsuru Kobayashi, attending separate gender-specific schools, impulsively swap places to experience life from a different perspective. As they navigate the complexities of their dual lives, romantic entanglements emerge, blurring the lines between truth and deception. A heartfelt confession leads Megumu to an unexpected kiss with upperclassman Aoi Sanada, sparking introspection about his own feelings. Meanwhile, Mitsuru's encounter with the school's queen bee, Azusa Tokugawa, stirs newfound emotions. Amidst blossoming relationships, the twins' hidden identities remain a ticking time bomb, threatening to unravel their carefully constructed charade.